Closure cap

ABSTRACT

A closure cap ( 1 ) for a container consists essentially of a cap base ( 2 ), of a cap skirt ( 3 ) and of a sealing disk ( 5 ) which bears at least partly on the cap base ( 2 ). A circumferential bulge ( 6 ) is arranged in the transition region ( 7 ) between the cap base ( 2 ) and the cap skirt ( 3 ). The bulge ( 6 ) serves for pressing the sealing disk ( 5 ) onto the container opening. The bulge ( 6 ) is divided by interruptions ( 8 ) into several blocks ( 9 ). On the inner side ( 10 ) of the cap base ( 2 ) there is arranged at least one rib ( 11 ) running radially outwards. The, rib seen in the circumferential direction, is located neighboring one of the interruptions.

BACKGROUND OF INVENTION

The invention relates to a closure cap that maybe brought intoengagement with a container.

Closure caps of plastic material are used in a multitude of applicationsfor closing containers. For achieving an adequate sealing effect, it isknown to lay a sealing inlay of a softer material onto the inner side ofthe cap base. So that the outer upper edge of the container to be closedis adequately sealed, it is for example known in EP 55 916, in theregion of the transition between the cap base and the cap skirt, toprovide a circumferential pressing bulge which presses the sealing diskagainst the edge of the container opening. With such a design, goodsealing results are achieved.

If such closures are used in combination with a container in which inthe course of time an increased inner pressure may build up, the goodsealing property may lead to certain problems. If the inner pressure inthe container, for example, increases by heating or by fermentation ofthe contents, on account of the good sealing there exists the risk thatthe container explodes.

EP 370 272 therefore suggests providing the circumferential bulge withsegment-like interruptions. In the region of these interruptions thesealing inlay may be pressed outwards. With this gas may escape and theinner pressure may be reduced.

The closure cap according to EP 370 272 is however burdened with thedisadvantage that in the region of the segment-like interruptions thesealing effect also with a normal inner pressure is no longer optimal.With this there exists the danger of leakages under normal conditions.

It is a goal to provide a closure cap which permits an adequate sealingof the container opening at normal conditions and which in spite of thispermits the reduction of an increased inner pressure.

SUMMARY

The closure cap for a container comprises a cap base and a cap skirt.The cap skirt is provided with inner retaining elements which can bebrought into engagement with outer retaining elements on the opening ofthe container. The closure cap furthermore comprises a sealing diskwhich at least partly lies on the cap base and which can be pressedagainst the opening of the container. The closure cap is furthermoreprovided with a bulge in the transition region between the cap base andthe cap skirt. The bulge serves for pressing the sealing disk onto theupper, outer edge of the opening of the container. The bulge isfurthermore divided by at least one segment-like interruption intoseveral blocks. If the inner pressure in the container rises, thesealing disk in the region of the interruptions may be forced radiallyoutwards, by which means a reduction of the inner pressure is madepossible. Of course the sealing disk may also be formed annularly.

The closure cap is, because of the venting behavior, above allparticularly suitable for carbonated beverages, fruit juices and hotfillings.

According to the present invention the cap base on its inner side isprovided with at least one rib running radially outwards. The ribextends radially at least over one sealing section on the inner side ofthe head plate. Sealing section here and in the following is to beunderstood as a section of the inner side of the head plate by way ofwhich the sealing disk can be pressed against the opening of thecontainer to be closed, in particular against the end-face side. The ribon the inner side of the cap base, seen in the circumferentialdirection, is arranged neighbouring the interruptions between theindividual blocks of the bulge for the pressing of the sealing disk.

The arrangement of the radial ribs neighbouring the interruptions leadsto a reliable sealing and in spite of this ensures venting of gas at anincreased inner pressure. With a normal pressure the sealing disk in theregion of the radial rib is pressed against the container opening. Alsoin the region of the interruption between the blocks of the bulgetherefore a good sealing is ensured. If however the inner pressure inthe container rises the cap base on account of the increased innerpressure is raised (so-called doming). With this the radial ribs arerelieved of pressure. The sealing effect of the sealing disk in theregion of the interruptions between the blocks of the bulge is as aresult reduced. The excess pressure may therefore vent particularly wellin the region of the rib and the interruption.

Preferably several interruptions are arranged in the bulge so that thereare formed several blocks. Advantageously at least one radial rib isarranged radially flush to each interruption. This leads to aparticularly uniform venting function. It is however also conceivable toarrange several radial ribs for each interruption. With several ribs,additionally between the ribs there is formed a venting channel intowhich the sealing disk may be displaced.

Preferably the angular extension of the ribs is selected smaller thanthe angular extension of the interruptions. As a result between theouter bordering line of the rib and the interruption between the blocks,additionally channels for venting are formed. With an increased innerpressure the sealing disk may be displaced into these channels.

Preferably the closure cap is roughly provided with 9 interruptions and9 blocks and radial ribs. This value corresponds to an optimalcompromise between sealing and bleeding properties.

The interruptions advantageously extend over an angle of about 5° to30°.

For increasing the pressing of the sealing disk additionally on the capbase there is provided a circumferential rib which has a lesserthickness than the radial rib.

The invention is hereinafter described in more detail in embodimentexamples and by way of the drawings.

BRIEF DESCRIPTION OF THE FIGURES:

FIG. 1 perspective representation of a cutout of a closure cap accordingto the invention;

FIG. 2 a view from below of a closure cap without a sealing disk, and

FIG. 3 a cross section through a cutout of a closure cap according tothe invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

In FIG. 1, perspectively and in section there is shown a cutout of aclosure cap 1. The closure cap 1 comprises a cap base 2 and a cap skirt3. The cap skirt 3 in a transition region 7 meets the cap base 2. On theinner side of the cap skirt 3 there is arranged a screw thread 4 forfastening the closure cap I onto a container 20 (see FIG. 3). In thetransition range 7 there is arranged a circumferential bulge 6. Thebulge 6 serves the pressing of a flexible sealing disk 5 (in FIG. 1 notshown, see FIG. 3) onto the opening of the container 20. The bulge 6 issubdivided into individual blocks 9 by segment-like interruptions 8.

On the inner side 10 of the cap base 2 there are arranged ribs 11extending radially outwards. The ribs 11 extend radially until roughlyin the region of the interruptions 8. With this it is essential that thesealing ribs 11 extend at least over one sealing section 12. The sealingsection is defined by that region in which a sealing disk 5 by way ofthe effect of the cap base 10 or the sealing ribs 11 can be pressedagainst the opening of the container 20.

In FIG. 2 the closure cap of FIG. 1 is shown from below. Forsimplification of the representation the sealing disk 5 is likewise notshown. A multitude of individual blocks 9 are arranged in the transitionregion 7 between the cap base 2 and the cap skirt 3. The individualblocks 9 are separated from one another by interruptions 8. For eachinterruption 8 there is provided a rib 11 extending radially outwards.The ribs 11, the blocks 9 and the interruptions 8 are distributeduniformly in the circumferential direction over the inner side 10 of thecap base 2.

FIG. 3 shows a cutout of a closure cap 1 according to the invention incross section. The closure cap 1 with the cap skirt 3 is held on theneck of a container 20 by way of a screw thread 4. A sealing disk 5 islayed into the closure cap 1. The sealing disk 5 contacts essentiallythe inner side 10 of the cap base 2. The sealing disk 5 by the effect ofthe inner side 10 of the cap base 2 is pressed against the upper outeredge 21 of the container opening. The circumferential bulge 6 isarranged between the cap base 2 and the cap skirt 3. The bulge 6comprises interruptions 8.

Furthermore, on the inner side 10 of the cap base 2 there is provided arib 11 extending radially from the inside to the outside. The rib 11presses the sealing disk 5 against the upper edge of the containeropening 20 in a specific manner. The rib 11 extends essentially over asealing section 12. In the sealing section 12 the sealing disk 5 ispressed against the container opening.

As shown in FIG. 2 for each interruption, between two blocks 9 there isarranged a radial rib 11. With a normal inner pressure the sealing disk5, except in the region of the interruptions 8, is pressed by the blocks9 against the upper outer edge 21 of the container and thereby seals. Inthe region of the interruptions 8, the sealing disk 5 is not pressedagainst the outer edge. By way of the ribs 11, however, the sealing disk5 is pressed against the upper edge of the container opening. If thepressure in the container increases, the cap base 2 is curved upwards inthe arrow direction R (so-called doming). With the doming the sealingdisk 5 by way of the blocks 9 is still further sealingly pressed againstthe outer, upper edge of the container opening. However the ribs 11 leadto a relieving of pressure of the sealing disk 5 in the region of theinterruptions 6. By way of this a path for venting is formed. The gas inthe inside of the container closed by the closure cap 1 may escapebetween the individual blocks 9 through the interruptions 8. In FIG. 3an interruption 8 is schematically shown. The blocks 9 are shown withdashed lines. The arrow V shows the way by which the gas reduction iseffected.

What is claimed is:
 1. A closure cap for a container comprising a capbase with an inner side a cap skirt with inner retaining elements whichmay be brought into engagement with outer retaining elements on theopening of the container, a sealing disk which at least partly bears onthe cap base and with a bulge in a transition region between said capbase and said cap skirt for pressing said sealing disk onto an upper,outer edge of such opening of the container, wherein said bulge issubdivided by at least one segment-like interruption, into severalblocks, wherein said inner side of said cap base has at least one ribwhich runs radially outwards and which extends radially at least over asealing section on said inner side of said cap base and wherein said ribseen in the circumferential direction is arranged neighbouring one ofsaid interruptions.
 2. A closure cap according to claim 1, wherein thereare several interruptions, and wherein at least on rib is arrangedradially flush to each interruption.
 3. A closure cap according to claim1, wherein said rib has an angular extension smaller than the angularextension of said interruption.
 4. A closure cap according to claim 1,wherein the closure cap has three to ten interruptions, three to tenblocks and three to ten radial ribs.
 5. A closure cap according to claim1, wherein said interruptions extend over an angular range of 5° to 30°.